Interfacial area transport of steam-water two-phase flow in a vertical annulus at elevated pressures during sub-cooled boiling

The interfacial area transport of steam-water two-phase flow in a vertical annulus has been investigated experimentally and theoretically for elevated pressures (a maximum of 1 MPa) during sub-cooled boiling. The modeling of interfacial area transport equation with phase change terms was introduced and discussed along with experimental results. The interfacial area transport equation considered the effects of bubble interaction mechanisms such as bubble breakup and coalescence, as well as, effects of phase change mechanisms such as wall nucleation and condensation for sub-cooled boiling. The benchmark focused on the sensitivity analysis of the constitutive relations that describe the phase change mechanisms. (author)